Biogen Idec Inc. BIIB +0.19% said its new multiple-sclerosis drug, Tecfidera, wasn't to blame for the death earlier this year of a 59-year-old woman who had taken the pill. In July, the Weston, Mass., biotech company said it was investigating the death of the woman from a form of pneumonia that the company said was common in multiple-sclerosis patients. She had taken Tecfidera for 5½ weeks before vomiting, diarrhea and other side effects prompted her to stop taking the pill, and died 2½ weeks after discontinuing treatment, the company had said.